1. Field of the Invention
The present invention relates to a radio base station apparatus for a mobile communication, in which communication is carried out on the basis of a code division multiple access (CDMA) method using spectrum spreading technique for a radio transmission.
2. Description of the Related Art
FIG. 1 shows a configuration example of a conventional radio base station apparatus in such a CDMA method. A radio base station apparatus 1 shown in FIG. 1 is composed of a call process and monitor controlling circuit 4 and shelves 2 and 3. The shelf is a unit in which the processes such as generation, spreading, and transmission of a transmission signal are controlled within the radio base station apparatus.
The call process and monitor controlling circuit 4 carries out the monitor and control of a state within the radio base station apparatus, resource management of a channel, and connection of a control call with respect to the control of origination and arrival.
The shelves 2 and 3 have the same configuration. Hereinafter, the shelf 2 will be described. Each of channel coding process circuits 6a and 6b receives a coding process data from the call process and monitor controlling circuit 4, and generates a transmission baseband signal. The coding process data is the data such as control data, user data of voice and packets, and data indicative of a kind of channel for carrying these data. Each of the channel coding process circuits 6a and 6b has units whose number corresponds to the number of channels. Each of merging circuits 7a and 7b merges the transmission baseband signals outputted from the channel coding process circuits 6a and 6b. Transmission signal processing circuits 5a and 5b spread and modulate the transmission baseband signals outputted from the merging circuits 7a and 7b, respectively. A radio transmission processing circuit 8a synthesizes and adds transmission spreading signals outputted from the transmission signal processing circuits 5a and 5b, and carries out orthogonal modulation, radio frequency conversion and amplification, and outputs a radio transmission signal from an antenna 9a. The radio transmission processing circuits 8a and 8b up-converts the transmission spreading signals to have radio transmission frequencies different from each other.
The shelf 2 receives and outputs a control signal as well as a data to be sent. The channel coding process circuits 6a and 6b and the transmission signal processing circuits 5a and 5b receive and output data such as coding process data, spreading process data, control data, and status data through a control bus from and to the call process and monitor controlling circuit 4. The spreading process data is a spreading code used when the transmission signal processing circuits 5a and 5b carry out the spreading modulation. Also, the transmission signal processing circuits 5a and 5b mutually receive and output an alarm signal when a fault has occurred.
The configuration and operation of the shelf 3 are similar to those of the shelf 2.
FIG. 2 is a block diagram showing a conventional configuration example of the transmission signal processing circuit 5a to 5d in the radio base station apparatus shown in FIG. 1. The respective transmission signal processing circuits have the same configuration. Here, only the transmission signal processing circuit 5a will be described. In FIG. 2, channel data separating circuit 11 separates individual channels from a transmission baseband signal, in which time divisional multiplexing is carried out to data for a plurality of channels received from the merging circuit 7a, in accordance with a channel data received from a CPU 20, and converts into a user data corresponding to a data rate for each user, and then outputs to an intra shelf transmission spreading process circuit 12. As described later, the intra shelf transmission spreading process circuit 12 has a current use system spreading circuit and a standby system spreading circuit. The channel data is the data to determine whether each user data should be processed by the current use system spreading circuit or the standby system spreading circuit. The intra shelf transmission spreading process circuit 12 carries out the spreading modulation to a plurality of user data whose data rates are different from each other, in accordance with a spreading process data (spreading code) received from the CPU 20, and outputs a spread signal for each user to an addition synthesizer 15d. 
The addition synthesizer 15d adds all the spread signals for the respective users to output to a format converter 17c. A synchronous pattern generating circuit 18c generates a synchronous pattern to output to the format converter 17c. The format converter 17c carries out an insertion of the synchronous pattern into the spread signal, and converts the spread signal to have a format adaptive for the transmission to the radio transmission processing circuit 8a. The format converter 17c outputs the spread signal on which the format conversion is carried out, as a transmission spread signal, through an output stopping circuit 19c to the radio transmission processing circuit 8a. 
When a fault has occurred in the transmission signal processing circuit 5a, an alarm detecting circuit 21 detects the fault. The alarm detecting circuit 21 outputs an alarm signal to the output stopping circuit 19c, the CPU 20 and the intra shelf transmission spreading process circuit 12 of the other transmission signal processing circuit 5b in the intra shelf (shelf 2). The intra shelf transmission spreading process circuit 12 in the transmission signal processing circuit 5a receives an alarm signal from the alarm detecting circuit 21 in the transmission signal processing circuit 5b when the fault has occurred in the transmission signal processing circuit 5b. 
When receiving the alarm signal from the alarm detecting circuit 21, the output stopping circuit 19c sets an output bus to a high impedance state, and stops the data output.
The intra shelf transmission spreading process circuit 12 has the current use system spreading circuit and the standby system spreading circuit. The current use system spreading circuit carries out a spreading process to the user data in the current use system received from the channel data separating circuit 11. The standby system spreading circuit carries out the spreading process to the user data in the standby system. Usually, the intra shelf transmission spreading process circuit 12 fixes the amplitude of a signal processed by the standby system spreading circuit to 0. However, the intra shelf transmission spreading process circuit 12 cancels the 0-fixation of the amplitude of the signal processed by the standby system spreading circuit, when receiving the alarm signal from the transmission signal processing circuit 5b (namely, when a fault has occurred in the other transmission signal processing circuits within the intra shelf).
The CPU 20 notifies the status data of the transmission signal processing circuit 5a to the call process and monitor controlling circuit 4 through the control bus, and receives the control data from the call process and monitor controlling circuit 4.
The configurations and operations of the transmission signal processing circuits 5b to 5d are similar to those of the transmission signal processing circuit 5a. 
In the radio base station apparatus shown in FIG. 1, any channel data separating circuit 11 of the transmission signal processing circuits 5a and 5b receives the transmission baseband signals outputted by the channel coding process circuits 6a and 6b. Then, in accordance with the channel data, the channel data separating circuit 11 of the transmission signal processing circuit 5a determines the user data to be outputted from the transmission signal processing circuit 5a, as a data corresponding to the current use system, and determines the user data to be outputted from another transmission signal processing circuit 5b within the intra shelf, as a data corresponding to the standby system. Also, the channel data separating circuit 11 of the transmission signal processing circuit 5b similarly determines the respective user data for the current use system and the standby system.
In the transmission signal processing circuits 5a and 5b, the output signals from the channel coding process circuits 6a and 6b are spread in the normal state by the current and standby system spreading circuits in the respective intra shelf transmission spreading process circuits 12. However, the amplitude of the signal processed by the standby system spreading circuit is fixed to 0. If a fault has occurred in the transmission signal processing circuit 5a, the output stopping circuit 19c of the transmission signal processing circuit 5a receives the alarm signal, and stops the data output. Also, the intra shelf transmission spreading process circuit 12 of the transmission signal processing circuit 5b receives the alarm signal, and cancels the 0-fixation of the amplitude of the signal processed by the standby system spreading circuit, and then outputs the spread signal which is processed by the standby system spreading circuit and should be originally outputted from the transmission signal processing circuit 5a. 
As mentioned above, in the radio base station apparatus shown in FIG. 1, the spreading process is carried out in the normal state by both the transmission signal processing circuits 5a and 5b. If any fault has occurred in one of the circuits 5a and 5b, the spreading processes to be carried out by the transmission signal processing circuits 5a and 5b are carried out only by one of the transmission signal processing circuits 5a and 5b in the normal state. The configuration in which the duplicated two transmission spreading processes (the transmission signal processing circuits 5a and 5b) as mentioned above are carried out in the normal state, and when the fault has occurred in one of the circuits 5a and 5b, only the circuit in the normal state carries out all the transmission spreading processes carried out by the two transmission spreading processes is referred to as a 0/1 configuration. Also, among them, one system is referred to as a 0-system, and the other system is referred to as a 1-system. In the 0/1 configuration, if a fault has occurred in one of the 0-system and the 1-system in the duplex structure, the normal system needs to have a function of compensating the spreading process. In the radio base station apparatus shown in FIG. 1, if the fault has occurred in the 0-system, the standby system spreading circuit within the 1-system compensates the 0-system. If the fault has occurred in the 1-system, the standby system spreading circuit within the 0-system compensates the 1-system.
Three methods including the configuration shown in FIG. 1 may be considered as the typical duplex configuration. FIG. 3 shows the configuration in the first method. In the configuration shown in FIG. 3, the spreading process in each of the transmission signal processing circuits 5a and 5b is not divided into the current use system and the standby system. One of the duplex transmission signal processing circuits 5a and 5b serves as the current use system to carry out the spreading process. The other is in a wait state as the standby system, and does not contribute to the transmission spreading process. If any fault has occurred in the current use system, the switching is carried out between the standby system and the current use system. Also, as shown in FIG. 3, the transmission baseband signals outputted from the channel coding process circuits 6a and 6b are not merged, and are supplied to the transmission signal processing circuits 5a and 5b. 
In such a method, it is necessary to design a hardware configuration in which the transmission signal processing circuit serving as the standby system stands by while carrying out the perfectly same process as the transmission signal processing circuit in the current use system. Thus, if the number of units in the channel coding process circuits 6a and 6b is increased in conjunction with the increase in the number of channels, the number of input signal lines to the channel data separating circuit in each transmission signal processing circuit is increased, which makes the circuit configuration of the channel data separating circuit complex and large, and makes it expensive.
The second method is the method using the 0/1 configuration described in FIG. 1. The second method is designed as follows. That is, the plurality of units of the channel coding process circuit are divided into two sections, which are set to the transmission signal processing circuits of the 0-system and the 1-system. Thus, the number of input signal lines supplied to the channel data separating circuit in each transmission signal processing circuit can be half the number of the first method. Also, in order that if any fault has occurred in one of the systems, the other system in the normal state carries out the process of the system, the outputs of the halved channel coding process circuits is multiplexed, and a transmission rate of a data are multiplexed. Hence, the data having the same amount as the first method is supplied to each channel data separating circuit.
The third method has the configuration similar to that of the second method. In the third method, one of the duplex transmission signal processing circuits 5a and 5b serves as the current use system and carries out the spreading process. If any fault has occurred in the transmission signal processing circuits carrying out the spreading process as the current use system, the switching is carried out between the standby system and the current use system. The third method requires the switching to the standby system when the fault has occurred in the channel coding process circuit physically connected to the transmission signal processing circuits in the current use system. For this reason, the third method has a defect that the switching sequence at this time becomes complex. Also, it is necessary that a merging circuit for merging a signal outputted from the channel coding process circuit corresponding to the other system is connected to each transmission signal processing circuits. Thus, various restrictions are put on a time of installation, a time of the fault occurrence, a time of maintenance and the like. Therefore, this implies the lack of flexibility of an apparatus. Even if an integral circuit of the channel coding process circuit and the merging circuit is used, this circuit must be connected to each transmission signal processing circuits.
As mentioned above, the second method shown in FIG. 1 has the following problems although it is superior to the first and third methods. The first problem is that the resources such as the channel coding process circuit, the spreading process circuit and the radio transmission processing circuit, which can be flexibly used, are limited to the internal portion of the shelf. The above resource implies the number of users that can be simultaneously processed by the respective circuits. In the second method, even if the number of users is increased in one shelf so that it becomes close to a limit value, the user data cannot be distributed to the other shelf.
The second problem is as follows. That is, when the control is carried out over the shelves, it is necessary to carry out a software process through the CPUs 20 in the transmission signal processing circuits 5a to 5d and the call process and monitor controlling circuit 4. Thus, the processing times in the switching control becomes longer.
In conjunction with the above description, a radio base station transceiver control system is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 3-120917). In this reference, a radio base station is composed of a plurality of transceivers, each of which includes a transmitter for a radio control channel and a receiver corresponding to the transmitter. Each of the transmitter and the receiver has a switching function between a current use mode and a standby mode independently.
Also, a time divisional multiple access radio communication system is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 5-31968). In this reference, there are two transceivers for the system has a current use system and a standby system. When alarm signals indicative of faults are generated at a same time from the current use system and the standby system, a system is switched between the current use system and the standby system for every time interval. At this time, a transceiver in which a fault has occurred is detected based on the alarm signal and the other transceiver is automatically set to the current use system.
Also, a duplex apparatus of a radio communication system is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 10-65579). In this reference, the duplex apparatus is composed of a main signal distributor 11 which has an interface 15 for one direction communication and an interface 16 for bi-direction communication, base stations 17 to 19, communication lines 107, 110 for connecting between the main signal distributor 11 and the radio base station 17 and between the main signal distributor 11 and the n-th (n is an integer equal to or more than 2) radio base station 19, and communication lines 108, 109 between the radio base stations 17 and 18 and 18 and 19. When there is a fault on the communication line between the radio base stations 17 and 18, the main signal distributor 11 sends out a signal of the same content to the interfaces 15, 16, after instructing the communication direction of the communication line to the n-th radio base station 19 and the second radio base station 18 from the interface 16.
Also, a transmission system for a base station is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 11-313012). In this reference, when a fault has occurred in a synchronization compensation section 8 (SYS4) while a standby synchronization compensation section 10 carries out a synchronization compensation processing for the SYS3 system in place of a synchronization compensation section 7 (SYS3) because a fault has occurred in the synchronization compensation section 7, data of SYS4 is taken in by the other system decoder section of the standby synchronization compensation section 10. An output connection control unit of the standby synchronization compensation section 10 is set to be connected with one output to the output of a transmission apparatus 13 of SYS3, and the other output to the output of the transmission apparatus 14 of SYS4.
Also, a radio base station control system is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 11-341547). In the reference, a first radio apparatus is composed of a first operation channel radio section for carrying out radio transmission and reception on a current use channel, a first current use channel radio control section for carrying out operation control at the first operation channel radio section, a first maintenance channel radio section for carrying out radio transmission and reception on a maintenance channel, a first maintenance channel radio control section for carrying out operation control at the first maintenance channel radio section, and a first radio base station control unit for controlling the first maintenance channel radio control section of the first current use channel radio control section. A second radio apparatus is composed of a second current use channel radio section for carrying out radio transmission and reception on a current use channel, a second current use channel radio control section for carrying out operation control at the second operation channel radio section, a second maintenance channel radio section for carrying out radio transmission and reception on a maintenance channel, a second maintenance channel radio control section for carrying out operation control at the second maintenance channel radio section, and a second radio base station control unit for controlling the second maintenance channel radio control section of the second current use channel radio control section. The radio base station control apparatus is composed of the first radio apparatus, the second radio apparatus, a first power supply section for supplying said first radio apparatus with power, a second power supply section for supplying the second radio apparatus with power, and a control board for the base station having the function to selectively connect with the first and second radio base station control units and to carry out and monitor the operation control of the first and second radio apparatuses. The first and second radio base station control unit detect the existence or non-existence of the fault in the first and second radio apparatuses by self monitor and mutual monitor of said and 2nd radio apparatus and set one to a current use system, and the other to standby system.
Therefore, an object of the present invention is to provide a radio base station apparatus which carries out the control over the shelves in a short time.
Another object of the present invention is to provide a radio base station apparatus which has a redundant configuration.
Still another object of the present invention is to provide a radio base station apparatus which effectively controls the resources such as channel coding process circuits, spreading process circuits, and a radio transmission processing circuit.
Yet still another object of the present invention is to provide a radio base station apparatus which uses inter-shelf communication.
In an aspect of the present invention, a radio base station apparatus includes first and second shelves. The first shelf includes a first shelf current use system transmission signal processing circuit, a first shelf standby system transmission signal processing circuit and a first shelf radio transmitting section. The first shelf current use system transmission signal processing circuit generates a first inter-shelf signal from a first shelf current use system baseband signal, and generates a first shelf current use system spread signal from the first shelf current use system baseband signal and a second inter-shelf signal. The first shelf standby system transmission signal processing circuit generates a third inter-shelf signal from a first shelf standby system baseband signal, and generates a first shelf standby system spread signal from the first shelf standby system baseband signal and a fourth inter-shelf signal. The first shelf radio transmitting section has a first shelf antenna and generates a first shelf radio signal from the first shelf current use system spread signal and the first shelf standby system spread signal to transmits from the first shelf antenna. The second shelf includes a second shelf current use system transmission signal processing circuit, a second shelf standby system transmission signal processing circuit and a second shelf radio transmitting section. The second shelf current use system transmission signal processing circuit generates the second inter-shelf signal from a second shelf current use system baseband signal, and generates a second shelf current use system spread signal from the second shelf current use system baseband signal and the first inter-shelf signal. The second shelf standby system transmission signal processing circuit generates the fourth inter-shelf signal from a second shelf standby system baseband signal, and generates a second shelf standby system spread signal from the second shelf standby system baseband signal and the third inter-shelf signal. The second shelf radio transmitting section has a second shelf antenna and generates a second shelf radio signal from the second shelf current use system spread signal and the second shelf standby system spread signal to transmits from the second shelf antenna.
The first shelf current use system transmission signal processing circuit includes a first output control circuit, a detecting circuit and a control circuit. The first output control circuit stops output of the first shelf current use system spread signal in response to an output stop control signal. The detecting circuit detects a fault in the first shelf current use system transmission signal processing circuit to generate an intra alarm signal. The control circuit outputs the output stop control signal to the first output control circuit in response to the intra alarm signal.
In this case, the transmission signal processing circuit may further include a second output control circuit which stops output of the first inter-shelf signal in response to the output stop control signal.
Also, the first shelf current use system transmission signal processing circuit may further include a first amplitude control circuit which controls a spread signal corresponding to the first shelf current use system spread signal in response to a second shelf current use system fault signal such that amplitude of the spread signal is 0. The control circuit outputs the second shelf current use system fault signal to the first amplitude control circuit when the intra alarm signal or an alarm signal indicating a fault of the second shelf current use system transmission signal processing circuit is present and a switching signal from the first shelf standby system transmission signal processing circuit and an alarm signal indicating a fault of the second shelf standby system transmission signal processing circuit are not present.
In this case, the transmission signal processing circuit may further include a second output control circuit which stops output of the first inter-shelf signal in response to the output stop control signal.
Also, the first shelf current use system transmission signal processing circuit may further include a second amplitude control circuit which controls a spread signal corresponding to the first inter-shelf signal in response to the second shelf current use system fault signal such that amplitude of the spread signal is 0.
Also, the first shelf current use system transmission signal processing circuit may further include an alarm detecting circuit which generates the alarm signal indicating the fault of the second shelf current use system transmission signal processing circuit based on no reception of the second inter-shelf signal from the second shelf current use system transmission signal processing circuit. Alternatively, the first shelf current use system transmission signal processing circuit may include an alarm detecting circuit which generates the alarm signal indicating the fault of the second shelf current use system transmission signal processing circuit based on an intra alarm signal generated in the second shelf current use system transmission signal processing circuit.
Also, the first shelf current use system transmission signal processing circuit may include a channel separating circuit, a first processing circuit and a second processing circuit. The channel separating circuit separates the first shelf current use system baseband signal into first and second channel signals. The first processing circuit spreads and synthesizes the first channel signals into a first spread signal. The second processing circuit spreads and synthesizes the second channel signals into a second spread signal to output as the first inter-shelf signal.
Here, each of the first and second processing circuits may include a current use system spreading circuit and a standby system spreading circuit. In this case, each of the first and second processing circuits may set to 0, amplitude of each of spread signals spread by a corresponding one of the standby system spreading circuits when the intra alarm signal of the first shelf current use system transmission signal processing circuit is not present and a switching request signal from the first shelf standby system transmission signal processing circuit is not present, and synthesize the spread signals spread signals spread by the corresponding standby system spreading circuit without setting the amplitudes to 0, when the intra alarm signal of the first shelf current use system transmission signal processing circuit or the switching request signal from the first shelf standby system transmission signal processing circuit is present.
Alternatively, the first shelf current use system transmission signal processing circuit may further include a synthesizing circuit which synthesizes the first spread signal and an other spread signal as the second inter-shelf signal into a spread signal corresponding to the first shelf current use system spread signal.
Also, the first shelf current use system transmission signal processing circuit may include a channel separating circuit, a first processing circuit and a second processing circuit. The channel separating circuit separates the first shelf current use system baseband signal into first and second channel signals. The first processing circuit spreads and synthesizes the first channel signals into a first spread signal. The second processing circuit converts the second channel signals into a baseband signal as the first inter-shelf signal.
Here, the first processing circuit may include a current use system spreading circuit and a standby system spreading circuit. In this case, the first processing circuit may set to 0, amplitude of each of spread signals spread by the standby system spreading circuit when the intra alarm signal of the first shelf current use system transmission signal processing circuit is not present and a switching request signal from the first shelf standby system transmission signal processing circuit is not present, and synthesize the spread signals spread signals spread by the standby system spreading circuit without setting the amplitudes to 0, when the intra alarm signal of the first shelf current use system transmission signal processing circuit or the switching request signal from the first shelf standby system transmission signal processing circuit is present.
Also, the first shelf current use system transmission signal processing circuit may further include a synthesizing circuit which synthesizes the first spread signal and an other spread signal obtained from the second inter-shelf signal into a spread signal corresponding to the first shelf current use system spread signal.
Also, the first shelf current use system transmission signal processing circuit may further include a second processing circuit which separates the second inter-self signal into third channel signals, and spreads and synthesizes the third channel signals into the other shelf spread signal.